osfmk/ppc/db_disasm.c

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /*
  29  * @OSF_COPYRIGHT@
  30  */
  31
  32 /*
  33  * Instruction disassembler.
  34  */
  35
  36 #include <mach/boolean.h>
  37 #include <machine/db_machdep.h>
  38
  39 #include <ddb/db_access.h>
  40 #include <ddb/db_sym.h>
  41 #include <ddb/db_output.h>
  42
  43 #include <kern/task.h>
  44 #include <kern/misc_protos.h>
  45
  46 #include "ppc_disasm.h"
  47
  48 db_addr_t       db_disasm_pc, db_disasm_symaddr;
  49 boolean_t       db_disasm_print_symaddr;
  50
  51 /*
  52  * Disassemble instruction at 'loc'.  'altfmt' specifies an
  53  * (optional) alternate format.  Return address of start of
  54  * next instruction.
  55  */
  56 db_addr_t
  57 db_disasm(db_addr_t loc, __unused boolean_t altfmt, task_t task)
  58 {
  59         int inst;
  60         char *p;
  61
  62         inst = db_get_task_value(loc, 4, FALSE, task);
  63         db_disasm_pc = loc;
  64         db_disasm_print_symaddr = FALSE;
  65         p = in(inst);
  66         db_printf("%s", p);
  67         if (db_disasm_print_symaddr) {
  68                 db_printf(" <");
  69                 db_task_printsym(db_disasm_symaddr, DB_STGY_ANY, task);
  70                 db_printf(">");
  71         }
  72         db_printf("\n");                /* Make sure we have a new line for multiline displays */
  73         dis_done();
  74         return (loc+4);
  75 }
  76
  77 /*
  78  * Given four bytes of instruction (stored as an int, not an
  79  * array of characters), compute if the instruction reads
  80  * memory.
  81  */
  82 int
  83 db_inst_load(__unused unsigned long insw)
  84 {
  85 #if 1
  86         db_printf("db_inst_load: coming soon in a debugger near you!\n");
  87         return 0;
  88 #else
  89         unsigned char insb, bits;
  90
  91         insb = insw & 0xff;
  92         insw >>= 8;
  93         bits = db_ldstrtab[insb];
  94         if (!(bits & DBLS_LOAD))
  95                 return (0);
  96         while (1) {
  97                 switch (bits & DBLS_MODS) {
  98                 case 0:
  99                         return (1);
 100                 case DBLS_MODRM:
 101                         insb = insw & 0xff;
 102                         return ((insb & 0xc0) != 0xc0);
 103                 case DBLS_SECOND|DBLS_MODRM:
 104                         insb = insw & 0xff;
 105                         return ((insb & 0xc0) != 0xc0 ? 2 : 0);
 106                 case DBLS_SECOND:
 107                         return (2);
 108                 case DBLS_ESCAPE:
 109                         insb = insw & 0xff;
 110                         insw >>= 8;
 111                         bits = db_ldstrtab0f[insb];
 112                         break;
 113                 case DBLS_SWREG:
 114                         return (db_inst_swreg(TRUE, insw, insb));
 115                 default:
 116                         panic ("db_inst_load: unknown mod bits");
 117                 }
 118         }
 119 #endif
 120 }
 121
 122 /*
 123  * Given four bytes of instruction (stored as an int, not an
 124  * array of characters), compute if the instruction writes
 125  * memory.
 126  */
 127 int
 128 db_inst_store(__unused unsigned long insw)
 129 {
 130 #if 1
 131         db_printf("db_inst_store: coming soon in a debugger near you!\n");
 132         return 0;
 133 #else
 134         unsigned char insb, bits;
 135
 136         insb = insw & 0xff;
 137         insw >>= 8;
 138         bits = db_ldstrtab[insb];
 139         if (!(bits & DBLS_STORE))
 140                 return (0);
 141         while (1) {
 142                 switch (bits & DBLS_MODS) {
 143                 case 0:
 144                         return (1);
 145                 case DBLS_MODRM:
 146                         insb = insw & 0xff;
 147                         return ((insb & 0xc0) != 0xc0);
 148                 case DBLS_SECOND|DBLS_MODRM:
 149                         insb = insw & 0xff;
 150                         return ((insb & 0xc0) != 0xc0 ? 2 : 0);
 151                 case DBLS_SECOND:
 152                         return (2);
 153                 case DBLS_ESCAPE:
 154                         insb = insw & 0xff;
 155                         insw >>= 8;
 156                         bits = db_ldstrtab0f[insb];
 157                         break;
 158                 case DBLS_SWREG:
 159                         return (db_inst_swreg(FALSE, insw, insb));
 160                 default:
 161                         panic ("db_inst_store: unknown mod bits");
 162                 }
 163         }
 164 #endif
 165 }
 166
 167 /*
 168  * Extra routines for the automatically generated disassembler
 169  */
 170 char *
 171 hex(
 172         bits n)
 173 {
 174         char *p;
 175
 176         if (n < 10)
 177                 return dec(n);
 178         p = dis_alloc(11);
 179         sprintf(p, "0x%lx", n);
 180         return p;
 181 }
 182
 183 char *
 184 dec(
 185         bits n)
 186 {
 187         char *p = dis_alloc(11);
 188         sprintf(p, "%lu", n);
 189         return p;
 190 }
 191
 192 char *
 193 brdispl(
 194         bits displ,
 195         bits nbits)
 196 {
 197         int sign, extended;
 198
 199         sign = 1 << (nbits - 1);
 200         extended = (displ & sign ? displ - (sign << 1) : displ);
 201         db_disasm_symaddr = db_disasm_pc + (extended << 2);
 202         db_disasm_print_symaddr = TRUE;
 203         return hex(extended << 2);
 204 }
 205
 206 char *
 207 mbz(bits n)
 208 {
 209         return n ? "[reserved bits not zero]" : "";
 210 }
 211
 212 size_t db_disasm_string_size = 0;
 213 #define DB_DISASM_STRING_MAXSIZE        4096
 214 char db_disasm_string[DB_DISASM_STRING_MAXSIZE];
 215
 216 void *db_disasm_malloc(size_t size);    /* forward */
 217 void *
 218 db_disasm_malloc(
 219         size_t size)
 220 {
 221         void * new_buf;
 222
 223         if (db_disasm_string_size + size <= DB_DISASM_STRING_MAXSIZE) {
 224                 new_buf = (void *) (db_disasm_string + db_disasm_string_size);
 225                 db_disasm_string_size += size;
 226                 return new_buf;
 227         }
 228         db_printf("db_disasm_malloc(size=%d) failed: %d left !\n",
 229                   size,
 230                   DB_DISASM_STRING_MAXSIZE - db_disasm_string_size);
 231         return (void *) 0;
 232 }